1. Field of the Invention
The present invention relates to a plant for desalination or purification of sea or brackish water by means of solar energy, having
a closed circuit comprising a thermal solar collector and a heat exchanger, in which circuit a heat transfer medium circulates,
a tank which can be charged with the sea or brackish water to be treated, and in which the heat exchanger is arranged to heat and evaporate the same,
a cooling surface which lies above the tank for condensation of the rising steam, and
water collectors which are arranged below part regions of the cooling surface for catching the condensed water.
2. The Prior Art
It is known that there is a shortage of drinking water on certain islands in the Mediterranean as well as in other regions. This problem is provisionally solved either by transport of drinking water from the mainland or by various energy-consuming processes (for example desalination of sea water by means of the method of reversing the osmotic pressure). A further classic possibility is the direct heating of the sea water by the sun in a tank, and specifically through a glass disc or a transparent film which serves as a cover at the same time, wherein evaporation and catching of condensed water are carried out with the aid of the same glass cover. U.S. Pat. Nos. 4,235,679 and 4,343,683, 4,525,242 and German Patent 4 321 192 are representative of the latest state of this art of desalination.
These classic possibilities either require very considerable energy or as is the case with methods which utilize solar energy--of very low efficiency, since in the known constructions the cover (glass disc) which is heated by the sun also serves as cooling a surface with resultant very high losses of evaporated water. Furthermore, these methods may not meet the necessary requirement, because they are associated with a limited capacity.
The invention therefore, aims at providing a plant for desalination or purification of sea or brackish water, which is not only of a considerably higher efficiency than known solutions, but also requires minimum space.